Various laundry products or additives are used in washing machines to maximize cleaning, fabric protection and the like. However, in order for many of these additives to be effective, it is often necessary to segregate the different additives when more than one is employed as the presence of one additive may adversely affect the others. Similarly, some additives are effective only at certain stages of the wash cycle. For instance, fabric softeners or other fabric treating agents must be added to the laundry in the washing machine during the final rinse portion of the wash cycle. If the fabric softener is added before, most of the softener is simply wasted. Thus, a consumer using an automatic washing machine will typically add detergent to the basket of the washing machine along with the soiled clothing and, subsequently, wait until the final rinse portion before adding fabric softener.
To make using fabric softeners more convenient, dispensers have been developed which release a liquid additive to the clothe basket of a washing machine at the appropriate phase after the wash cycle. Examples of these are found in U.S. Pat. No. 2,991,911 to Spain, U.S. Pat. No. 2,534,014 to Gayring et al., and U.S. Pat. No. 3,233,794 to Sisler. Unfortunately, these prior art devices exhibit a number of deficiencies. One shortcoming is that they are rather complex and expensive. They further require attachment and some integration into the workings of the washing machine with which they are used, and therefore materially add to cost. These devices typically may not be merely added to an existing washing machine but must be built into the machine at the factory, thus making them virtually useless for existing washing machines that have been sold without such automatic dispenser capability.
Another approach to improving consumer convenience is the multi-use approach wherein two or more laundry additives are included on a single delivery substrate. The multi-use approach contemplates depositing two or more additives targeted at different phases of a laundry cycle, e.g. detergent plus a fabric softener, upon or within a delivery substrate. The substrate is added to the washer at the start of the laundry cycle, and is designed to dispense the additive at the stage of the wash cycle where the additive is most effective.
There are several drawbacks associated with multi-use compositions of the art. Typically, delivery of each additive does not occur exactly at the stage of the wash cycle where its use is most efficient. Multi-use packages are often inefficient owing to their fixed proportions of the various additives. The consumer thus cannot vary the amount of a particular additive without altering the amount of the remaining additives. In many cases, delivery of a particular additive does not occur, or incompletely occurs, when intended. This severely reduces performance of the additive. Some additives can interact with their co-additives, also severely reducing their performance. Most multi-use additives include the additive, e.g. fabric softener, with the detergent composition, and such detergents usually hamper the performance of such softeners. The detergent/softener compositions are thus relatively easy to use, but do not work well.
Another approach to obtaining the convenience of multi-use compositions with the effectiveness and flexibility of single-use additives is to provide a means for dispensing the additive at the desired point(s) in the cycle. Typically such a dispenser is a mechanical device built into the washing machine, and has a limited capability for dispensing additives. Many of these dispensers are suited to dispense only liquid additives and usually are made by the appliance manufacturers to fit only certain models of washing machines that they also manufactured. A number of patent references describe dispensers that use centrifugal force developed by a washing machine during a spin phase to effect release of an additive. The centrifugal dispensers of the art appear to fall into two categories: (a) passive dispensers with no moving parts which rely entirely on centrifugal force to release the additive; and (b) active dispensers which utilize centrifugal force to effect a change in configuration of the dispenser, causing the release of the additive.
Generally, the prior art dispensers of the first type are suited to dispense only liquid additives, which are effective only if delivered in the rinse. The second class of prior art dispensers are often complex, and/or are limited in their application to a small number of washing machine agitators. The liquid additives suffer the disadvantage of being inconvenient, and often messy to use, while the mechanical dispensers necessary to dispense the liquid additive generally must be provided by the manufacturer with the washing machine, and cannot be retrofitted.
The first category of prior art dispensers describe, in general, a two-chamber dispenser that is mounted on top of an agitator. An inner chamber has outwardly sloping walls and is initially filled with the additive. Coakial with and having larger diameter than this inner chamber is an outer chamber with straight walls and often a circumferential channel. At the bottom of the second chamber are one or more apertures that allow the additive to drain into the tub of the washing machine. With this type of dispenser, a liquid additive to the inner chamber and during the spin phase, centrifugal force causes the additive to flow out over the sloping walls and into the second chamber, where it continues to flow under the influence of centrifugal force into the circumferential channel. When the spin phase ends, the additive flows by gravity out or the apertures at the bottom of the second chamber and into the tub as it is filling with rinse water. Dispensers of this type are disclosed, for example, by U.S. Pat. No. 4,240,277 to Manthei, U.S. Pat. No. 4,186,574 to Sundstrom, U.S. Pat. No. 4,118,957 to Marcussen, U.S. Pat. No. 3,736,773 and U.S. Pat. No. 3,699,785 both to Waugh, U.S. Pat. No. 3,620,054 to Drews et al, U.S. Pat. No. 3,596,480 and U.S. Pat. No. 3,330,135 both to Douglas, U.S. Pat. No. 3,481,163 to Bochan et al., and U.S. Pat. No. 4,478,059 Yates.
Other dispensers which rely on centrifugal force to release an additive, but which are not attached to the agitator include free body dispensers having a balloon-like additive reservoir that releases additive under pressure generated by spin phase centrifugal forces, especially if the reservoir is sandwiched between a laundry load and the sidewall of the machine. See for, example, U.S. Pat. No. 4,379,515 to Townsend. U.S. Pat. No. 4,186,573 to Brenner et al. describes a centrifugally actuated two-chamber dispenser which hangs on the rim of the wash tub; operation of this device is similar to the agitator-mounted two-chamber dispensers, i.e., centrifugal fill of an outer chamber and gravity flow after the spin ceases.
There are numerous prior art centrifugal force operated dispensers that effect a mechanical change in the dispenser and that indirectly cause the dispensing of the additive. U.S. Pat. No. 4,420,951 to Clearman et al. describes a dispenser apparatus that is mounted on an agitator that includes a water pump and a nozzle. Under centrifugal force created by the spin, the nozzle is redirected to aim a flow of water into a portion of the dispenser containing the additives. U.S. Pat. No. 4,026,131 to Dugger describes a pouch containing an additive and constructed such that a seal on the pouch is broken under the centrifugal force of the spin, freeing the additive. U.S. Pat. No. 3,757,544 to Olthuis describes an agitator-mounted dispenser that is held above the water level during the wash. During the spin phase the centrifugal force releases a catch on the dispenser causing it to fall below the rinse water level. T993,001 (U.S. Defensive Publication) to McCarthy describes a spin actuated dispenser having a mass attached to a valve. U.S. Pat. No. 4,260,054 to Bory et al. discloses non-soluble sheets having partially serrated phases that rupture under spin-generated centrifugal force, releasing an additive. U.S. Pat. No. 3,888,391 to Merz discloses a dispenser that releases additive via a centrifugally actuated valve. U.S. Pat. No. 3,670,530 to Filipak shows a dispenser that may be attached to the agitator and comprises a pivotable cup that pivots from vertical to horizontal during spin, pouring out the additive.
In view of the deficiencies of the existing art, there remains a need for a simple, reliable mechanical dispenser, which can be used with a wide variety of existing commercially available washing machines, for dispensing a laundry additive into the washing machine during a selected phase of the washing cycle.